1. Field of the Invention
One or more embodiments of the present invention relate to a method, medium, and system rendering 3D graphics data, and more particularly, to a method, medium, and system minimizing power consumption during graphics data rendering.
2. Description of the Related Art
Generally, three-dimensional (3D) graphics data is input to a renderer in units of a frame.
In such rendering, first, when graphics data corresponding to the current frame is input, a rendering engine initializes a Z buffer for storing depth values for each pixel forming an image represented by the input data, and a back buffer for storing color values of each pixel. Here, the depth values within the Z buffer are typically normalized to a maximum depth value that the buffer is capable of expressing, and the color values of the back buffer are typically normalized to color values corresponding to the background of a finalized image.
Then, the rendering engine performs transformation, lighting, and rasterization processes on all the objects in the graphics data. The transformation process is a process for transforming 3D objects into two-dimensional (2D) objects, the lighting process is a process of expressing visual effects of the transformed objects with respect to light sources, and the rasterization process is a process of assigning accurate colors to each of the pixels forming the transformed objects.
In the rasterization process, the rendering engine calculates respective depth and color values for each pixel forming an object, compares the calculated depth values for each pixel to the corresponding depth values of the depth buffer and revises the values of the depth buffer to the depth values of the corresponding pixels when the calculated depth values indicate that the corresponding pixels are closer than represented by the depth values of the depth buffer from the current viewpoint, and revises the values in the color buffer to the color values of the corresponding pixels. In order to display only the visible objects in the image, a visibility test is performed for each pixel.
When the rasterization process for all the objects included in the input data is completed, the rendering engine transfers the color values of each pixel stored in the back buffer to a front buffer to display the rendered image on a screen. Then, when the graphics data of the next frame is input, the rendering engine again initializes the Z buffer and the back buffer, and repeats the transformation, lighting, and rasterization processes for the objects included in the input graphics data.
This type of processing of input graphics data is called a graphics pipeline. A characteristic of a graphics pipeline is that the speed of the entire pipeline is delayed when any delay occurs in one component of the pipeline during processing. Therefore, each rendering image is given a deadline, and power is supplied from a power supply unit to render a frame of data within each deadline, and display the rendering results on the display.
Recently, more portable devices such as mobile communication terminals that provide 3D graphics rendering are being manufactured. Because such portable devices have limited battery capacities, it is crucial that they operate in the lowest power consuming modes possible compared to wired devices, such as desktop computers, which typically are not as limited in capacities.